Packages for high power semiconductor devices which can be surface mounted on an insulated metal substrate (IMS) or other flat support board surface are well known. One such package is shown in U.S. patent application Ser. No. 08/583,219, filed on Jan. 4, 1996, entitled SURFACE-MOUNT SEMICONDUCTOR PACKAGE which is incorporated herein by reference. Such packages are very well adapted for surface mounting to the conductive patterns of flat support boards such as an IMS structure (a thick copper or aluminum substrate covered by a thin insulation film which has a thin patternable copper or other conductive solderable upper surface).
The present invention is an improvement of the device of U.S. patent application Ser. No. 08/583,219, making it more efficient and more easily manufacturable.